[racket] heredoc syntax

Whats the syntax for heredoc strings?

I was surprised that I couldn't find documentation for the lexical structure of racket. I also grepped the source for 'heredoc' but didn't come up with anything.

I like python's heredoc syntax -- triple quotes. """a heredoc string""", if such a thing could be added to racket (I will most likely do something like this for 
honu).